As technology nodes decrease, parasitic capacitance and contact resistance for contact plugs becomes more difficult to control. In larger node technologies, borophosphosilicate glass (BPSG) or phosphosilicate glass (PSG) was used as an interlayer dielectric (ILD) layer material. Smaller technology nodes use flowable silicon dioxide (SiO2) as the ILD layer material. A dielectric value of the ILD layer material determines an amount of parasitic capacitance for conductive components embedded within the ILD layer.
In some approaches, the flowable SiO2 is doped using an in-situ process. For example dopants were added during a deposition or epitaxial process in order to reduce the dielectric value of the flowable SiO2. In some approaches, the flowable SiO2 is doped by implanting dopants into an already formed ILD layer to reduce the dielectric value.